Is there a role for targeted therapies in the collecting ducts of Bellini carcinoma? Efficacy data from a retrospective analysis of 7 cases

Though uncommon, the collecting duct carcinoma (CDC) of Bellini is a very aggressive primary renal tumour occurring in less than 1% of all renal cell carcinoma (RCC) cases. This rare subtype was always excluded from the prospective trials with targeted therapies. Few data so far available concern the subgroup analyses from the expanded access programs with sorafenib and sunitinib, and from temsirolimus randomized study. From December 2004 to May 2010, 333 patients with advanced RCC have been treated in our Institution with targeted therapies: of these, 7 (2.6%) were affected by CDC. General characteristics, symptoms, pathological features, treatments and patients' outcome were recorded. All patients affected by CDC received targeted agents as first-line therapy: more precisely, 4 patients were treated with sorafenib, 2 with temsirolimus and 1 with sunitinib. After progression 2 patients received a second-line treatment with sunitinib. No patients were alive at 5 years. Five patients developed early progression of disease with a very short 4-month survival, while 2 cases had a long-lasting disease control with an overall survival time accounting for 49 and 19 months, respectively. Treatment-related adverse events were manageable consisting of fatigue, diarrhoea, hand-foot syndrome, hypertension and anemia, the latter being the most frequent. No treatment discontinuations due to adverse event were needed. This investigation shows that targeted agents are safe, displaying some degree of activity in CDCs: therefore, they could be considered as an alternative in patients not eligible to chemotherapy regimens. Further studies including biomarkers as predictive factors of tumour biology and clinical features are required to improve the management of this challenging disease.